Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients / Asociaciones de las concentraciones de adiponectina y leptina con el desgaste proteico-energético en pacientes con nefropatía terminal

Objective: The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW. Design: Prospective (18 months). Setting: University Hospital of Heraklion, Crete, Greece. Subjects: Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD. Main outcome measures: At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW). Results: Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification. Conclusions: Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis (AU)

Objetivo: El objetivo del estudio era analizar la prevalencia del desgaste proteico-energético (DPE) en los pacientes en hemodiálisis (HD) y diálisis peritoneal (DP) de nuestro centro, y determinar si la adiponectina y la leptina intervienen en el desarrollo del DPE (AU). Diseño: Prospectivo (18 meses). Ámbito: Hospital Universitario de Heraklion, Creta, Grecia. Sujetos: Setenta y cuatro pacientes con nefropatía terminal, 47 en HD y 27 en DP. Variables principales: Se recogieron datos antropométricos, nutricionales y sobre el estado inflamatorio. También los valores séricos de adiponectina y leptina en cada punto temporal. Se dividió a los pacientes en 3 estratos en función de la intensidad del DPE (0, 1-2 y ≥3 criterios de DPE. Resultados: Las concentraciones de adiponectina y leptina eran mayores en los pacientes en DP que en los sometidos a HD (p≤0,035). Los valores de adiponectina eran incrementalmente mayores al aumentar el estrato de DPE (p≤0,002). La leptina mostraba la tendencia opuesta, con niveles más bajos en los pacientes desnutridos y más altos en los pacientes con ningún criterio de DPE (p≤0,042). Las alteraciones de las concentraciones de adiponectina durante el período de observación dependían del estrato de DPE (p≤0,021) y del modo de diálisis (p≤0,002), previo ajuste por edad, antigüedad de la diálisis, sexo e índice de grasa corporal. En particular, los valores de adiponectina aumentaban con el tiempo en los pacientes en HD con ≥3 criterios de DPE, mientras que descendían en los pacientes en DP con ≥3 criterios de DPE durante todo el estudio. Ni el modo de diálisis ni la estratificación en función del DPE influyeron en las alteraciones de la leptina. Conclusiones: Nuestro estudio aporta pruebas de que el aumento de las concentraciones de adiponectina y el descenso de los valores de leptina se asocian independientemente con el DPE y, en consecuencia, con un mal pronóstico (AU)

Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients.

OBJECTIVE: The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW. DESIGN: Prospective (18 months). SETTING: University Hospital of Heraklion, Crete, Greece. SUBJECTS: Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD. MAIN OUTCOME MEASURES: At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW). RESULTS: Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification. CONCLUSIONS: Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis.

Hsf-1 affects podocyte markers NPHS1, NPHS2 and WT1 in a transgenic mouse model of TTRVal30Met-related amyloidosis.

INTRODUCTION: Familial amyloid polyneuropathy is characterized by transthyretin (TTR) deposition in various tissues, including the kidneys. While deposition induces organ dysfunction, renal involvement in TTR-related amyloidosis could manifest from proteinuria to end-stage kidney failure. As proteinuria is considered result of glomerular filtration barrier injury we investigated whether TTR deposition affects either glomerular basement membrane (GBM) or podocytes. MATERIALS AND METHODS: Immunohistochemistry, immunoblot and gene expression studies for nephrin, podocin and WT1 were run on renal tissue from human-TTRV30M transgenic mice hemizygous or homozygous for heat shock factor one (Hsf-1). Transmission electron microscopy was used for evaluation of podocyte foot process width (PFW) and GBM thickness in Hsf-1 hemizygous mice with or without TTRV30M or amyloid deposition. RESULTS: Glomeruli of hsf-1 hemizygous transgenic mice showed lower nephrin and podocin protein levels but an increased podocyte number when compared to Hsf-1 homozygous transgenic mice. Nephrin, podocin and WT1 gene expression levels were unaffected by the Hsf-1 carrier status. TTRV30M deposition was associated with increased PFW and GBM thickness. CONCLUSIONS: Under the effect of Hsf-1 hemizygosity, TTRV30M deposition has deleterious effects on GBM thickness, PFW and slit diaphragm composition, without affecting nephrin and podocin gene expression.

Losartan affects glomerular AKT and mTOR phosphorylation in an experimental model of type 1 diabetic nephropathy.

The AKT-mTOR pathway is activated in diabetic nephropathy. Renin-angiotensin system modulators exert beneficial effects on the diabetic kidney. We explored the action of losartan on AKT-mTOR phosphorylation in glomeruli and podocytes. Diabetes mellitus was induced to Sprague-Dawley rats by streptozotocin. Five months later, the rats were commenced on losartan and euthanized 2 months later. Kidneys were processed for immunofluorescence studies. Glomeruli were isolated for Western blot analysis. Diabetes increased activated forms of AKT and mTOR both in glomeruli and podocytes. In diabetic rats, losartan decreased phosphorylated/activated forms of AKT (Thr308) and mTOR (Ser2448) in glomeruli but decreased only activated mTOR in podocytes. However, in both glomeruli and podocytes of healthy animals, an inverse pattern was evident. In conclusion, a new body of evidence indicates the differential activation of AKT-mTOR in glomeruli and podocytes of healthy and diabetic animals in response to losartan.

Human TTRV30M localization within podocytes in a transgenic mouse model of transthyretin related amyloidosis: does the environment play a role?

Transthyretin related amyloidosis is a nosological entity that leads to disability, diminished quality of life, all stages of chronic kidney disease and eventually death. Podocytes are polarized, highly differentiated epithelial cells important for proper nephron function. In the present study we investigated whether deposited TTRVal30Met (TTRV30M) molecules could be localized within podocytes in situ under the effect of different housing conditions (i.e. specific pathogen free [SPF] vs. non-SPF). Murine renal glomeruli from human TTRV30M (hTTRV30M) transgenic mice were examined via direct and indirect immunofluorescence techniques for the presence of hTTRV30M, murine serum amyloid P, activated caspase-3 and NPHS1. Association strength and amount of colocalization for NPHS1-hTTRV30M, NPHS1-activated caspase-3, hTTRV30M-murine serum amyloid P were estimated. Localization of hTTRV30M in podocytes was demonstrated by immuno-electron microscopy. Renal hTTRV30M gene and NPHS1 gene expression levels were estimated. Non-SPF transgenic mice showed increased glomerular hTTRV30M deposition compared to their SPF counterparts. Furthermore increased podocytic localization of hTTRV30M was noticed in non-SPF mice. Glomerular caspase-3 activation was increased only in the non SPF housing conditions. Podocytic caspase-3 activation was increased in SPF and in non-SPF transgenic mice when compared to non transgenic controls. Environmental conditions influence glomerular deposition and podocytic localization of hTTRV30M. In this context increased caspase-3 activation occurred.

Rapamycin induced ultrastructural and molecular alterations in glomerular podocytes in healthy mice.

BACKGROUND: In the normal kidney, rapamycin is considered to be non-nephrotoxic. In the present study, we investigated whether rapamycin is indeed non-nephrotoxic by examining the ultrastructural and molecular alterations of podocytes in healthy mice. METHODS: Balb/c mice were given three different intraperitoneal doses of rapamycin for 1 week (dose model)-low-dose group: 1 mg/kg/day, intermediate-dose (ID) group: 1.5 mg/kg/day and high-dose (HD) group: 3 mg/kg/day; four mice in each group. An ID of rapamycin was also given for three different periods (time model): 1, 4 and 8 weeks; four mice were in each group. Mice treated with dimethyl sulphoxide served as controls. Body weight was measured weekly. Renal function was assessed by serum creatinine at the time of sacrifice. For estimation of albuminuria, 24-h urine collections were performed before treatment and weekly thereafter. Glomerular content of nephrin, podocin, Akt and Ser473-phospho-Akt was estimated by western blot and immunofluorescence. Nephrin and podocin messenger RNA (mRNA) were measured by real-time polymerase chain reaction. Mean podocyte foot process width (FPW) was measured by electron microscopy. RESULTS: Urine albumin levels increased in the HD and 4-week groups. Renal function was modestly deteriorated in the HD group. The mean FPW increased in a dose-dependant manner at Week 1, further deteriorated at Week 4 and finally improved at Week 8. Nephrin and podocin mRNA levels showed a significant decrease at Week 1 and were restored at Week 4 and 8. Nephrin and podocin protein levels were reduced at Week 4 and recovered at Week 8. Ser473-phospho-Akt significantly increased in all rapamycin-treated groups. CONCLUSIONS: Rapamycin induced significant ultrastructural and molecular alterations in podocytes in association with albuminuria. These alterations happened early during treatment and they tended to improve over an 8-week treatment period.

The role of serum magnesium and calcium on the association between adiponectin levels and all-cause mortality in end-stage renal disease patients.

BACKGROUND: Adiponectin (ADPN) is the most abundant adipocyte-specific cytokine that plays an important role in energy homeostasis by regulating lipid and glucose metabolism. Studies of the impact of ADPN on clinical outcomes have yielded contradictory results so far. Here, we examined the association of ADPN with serum magnesium (s-Mg) and calcium (s-Ca) levels and explored the possibility whether these two factors could modify the relationship between ADPN and all-cause mortality in patients with end-stage renal disease. METHODOLOGY/PRINCIPAL FINDINGS: After baseline assessment, 47 hemodialysis and 27 peritoneal dialysis patients were followed- up for a median period of 50 months. S-Mg and s-Ca levels emerged as positive and negative predictors of ADPN levels, respectively. During the follow-up period 18 deaths occurred. There was a significant 4% increased risk for all-cause mortality for each 1-µg/ml increment of ADPN (crude HR, 1.04; 95% CI, 1.01-1.07), even after adjustment for s-Mg and s-Ca levels, dialysis mode, age, albumin and C-reactive protein. Cox analysis stratified by s-Mg levels (below and above the median value of 2.45 mg/dl) and s-Ca levels (below and above the median value of 9.3 mg/dl), revealed ADPN as an independent predictor of total mortality only in the low s-Mg and high s-Ca groups. Furthermore, low s-Mg and high s-Ca levels were independently associated with malnutrition, inflammation, arterial stiffening and risk of death. CONCLUSIONS/SIGNIFICANCE: The predictive value of ADPN in all-cause mortality in end-stage renal disease patients appears to be critically dependent on s-Mg and s-Ca levels. Conversely, s-Mg and s-Ca may impact on clinical outcomes by directly modifying the ADPN's bioactivity.

A feasibility study for the provision of electronic healthcare tools and services in areas of Greece, Cyprus and Italy.

BACKGROUND: Through this paper, we present the initial steps for the creation of an integrated platform for the provision of a series of eHealth tools and services to both citizens and travelers in isolated areas of the southeast Mediterranean, and on board ships travelling across it. The platform was created through an INTERREG IIIB ARCHIMED project called INTERMED. METHODS: The support of primary healthcare, home care and the continuous education of physicians are the three major issues that the proposed platform is trying to facilitate. The proposed system is based on state-of-the-art telemedicine systems and is able to provide the following healthcare services: i) Telecollaboration and teleconsultation services between remotely located healthcare providers, ii) telemedicine services in emergencies, iii) home telecare services for "at risk" citizens such as the elderly and patients with chronic diseases, and iv) eLearning services for the continuous training through seminars of both healthcare personnel (physicians, nurses etc) and persons supporting "at risk" citizens.These systems support data transmission over simple phone lines, internet connections, integrated services digital network/digital subscriber lines, satellite links, mobile networks (GPRS/3G), and wireless local area networks. The data corresponds, among others, to voice, vital biosignals, still medical images, video, and data used by eLearning applications. The proposed platform comprises several systems, each supporting different services. These were integrated using a common data storage and exchange scheme in order to achieve system interoperability in terms of software, language and national characteristics. RESULTS: The platform has been installed and evaluated in different rural and urban sites in Greece, Cyprus and Italy. The evaluation was mainly related to technical issues and user satisfaction. The selected sites are, among others, rural health centers, ambulances, homes of "at-risk" citizens, and a ferry. CONCLUSIONS: The results proved the functionality and utilization of the platform in various rural places in Greece, Cyprus and Italy. However, further actions are needed to enable the local healthcare systems and the different population groups to be familiarized with, and use in their everyday lives, mature technological solutions for the provision of healthcare services.

The PI3K/Akt/mTOR pathway is activated in murine lupus nephritis and downregulated by rapamycin.

BACKGROUND: The mammalian target of rapamycin (mTOR) inhibitor, rapamycin, has been shown to inhibit the progression of murine lupus nephritis by virtue of its potent immunosuppressive properties. The phosphoinositol-3-kinase (PI3K)/Akt pathway is a major upstream activator of mTOR and has been implicated in the propagation of cancer and autoimmunity. However, the activation status of the PI3K/Akt/mTOR pathway in lupus nephritis has not been studied so far. METHODS: In NZBW/F1 female mice, we examined the glomerular expression of Akt and mTOR by immunofluorescence and western blot. We also searched for specific phosphorylations of these kinases known to ensue during activation of the PI3K/Akt/mTOR pathway. In parallel, we examined the therapeutic role of rapamycin either before or after the development of overt lupus nephritis. RESULTS: We found that in untreated mice, as opposed to healthy controls, Akt and mTOR were over-expressed and phosphorylated at key activating residues. Rapamycin prolonged survival, maintained normal renal function, normalized proteinuria, restored nephrin and podocin levels, reduced anti-dsDNA titres, ameliorated histological lesions, and reduced Akt and mTOR glomerular expression activation. CONCLUSIONS: These results suggest that: (i) the PI3K/Akt/mTOR pathway is upregulated in murine lupus nephritis, thus justifying treatment with rapamycin; (ii) rapamycin not only blocks mTOR but also negatively regulates the PI3K/Akt/mTOR pathway; and (iii) rapamycin is an effective treatment of murine lupus nephritis. Examination of the PI3K/Akt/mTOR pathway may offer new insights into the pathogenesis of lupus nephritis in humans and may lead to more individualized and less toxic treatment.

Membranous nephropathy and lupus-like syndrome after hematopoietic cell transplantation: a case report.

INTRODUCTION: The kidney is increasingly recognised as a target organ of chronic graft-versus-host disease after hematopoietic cell transplantation in the context of the development of the nephrotic syndrome. Chronic graft-versus-host disease is associated with autoimmune phenomena similar, but not identical, to those observed in various rheumatologic disorders, implicating autoimmunity as an important component of the disease. CASE PRESENTATION: We report the case of a 57-year-old Caucasian man who developed the nephrotic syndrome due to membranous nephropathy in association with recurrent chronic graft-versus-host disease, along with a lupus-like syndrome manifested with pancytopenia, hair loss, positive anti-DNA antibodies and sub-epithelial and mesangial immune deposits. To the best of our knowledge, this is the first case reported in the literature. The nephrotic syndrome subsided soon after he was treated with a short course of cyclosporin with steroids. Unfortunately he died seven months later due to a relapse of leukemia. CONCLUSIONS: Our case report confirms the notion that chronic graft-versus-host disease is characterized by the appearance of autoimmune phenomena similar, but not identical, to those seen in autoimmune diseases. The decision for more immunosuppression has to be weighed against the need for preservation of the graft versus leukemia phenomenon.

Peritoneal dialysis-associated peritonitis: clinical features and predictors of outcome.

OBJECTIVES: The objective of this study was to identify the epidemiological, clinical, and microbiological factors affecting the outcome of peritoneal dialysis (PD)-associated peritonitis. METHODS: All patients with PD-associated peritonitis, cared for at the University Hospital of Heraklion from 1990 to 2007, were retrospectively studied. RESULTS: A total of 247 episodes of PD-associated peritonitis occurring in 82 patients were evaluated. The median age of patients was 68 years (range 10-92 years); 51 (62%) were males. There were 104 episodes (42%) of Gram-positive peritonitis, 46 (19%) of Gram-negative peritonitis, 13 (5%) of polymicrobial peritonitis, and 11 (4%) of fungal peritonitis. There were 64 (26%) complicated episodes. The latter included 22 (8.9%) relapses, 13 (5.3%) repeated episodes, 18 (7.3%) catheter removals, and 11 (4.5%) deaths. In multivariate analysis, the presence of a purulent exit-site infection (p<0.001), peritoneal dialysis effluent cell count >100 x 10(6)/l for more than 5 days (p<0.001), use of antimicrobials during the preceding 3 months (p<0.05), and low serum total protein level on admission (p<0.05) were independent predictors of a complicated course. CONCLUSIONS: Exit-site infection, more than 5 days with a peritoneal dialysis effluent cell count >100 x 10(6)/l, prior use of antimicrobials, and low serum total protein level are potential predictors of complicated PD-associated peritonitis and may distinguish high-risk cases.

Long-term complication rates and survival of peritoneal dialysis catheters: the role of percutaneous versus surgical placement.

Considerable controversy currently exists in the literature concerning the mode of catheter placement and its impact on the technical success of peritoneal dialysis (PD). We decided to compare the impact of the surgical versus the percutaneous insertion technique on peritoneal dialysis catheter (PDCs) complications and survival. Our study population comprised 152 patients in whom 170 PDCs were inserted between January 1990 and December 2007 at the main PD unit on the island of Crete. Eighty four catheters were surgically placed (S group) and 86 were placed percutaneously by nephrologists (N group). The total experience accumulated was 4997 patient-months. The overall complications did not differ between the two groups. Only early leakage was more frequent in N group than S group (10.3 versus 1.9 episodes per 1000 patient-months; p < 0.001). However, it was easily treated and did not constitute a cause of early catheter removal. Catheter survival was 91.1%, 80.7%, and 73.2%, in the S group versus 89.5%, 83.7%, and 83.7% for the N group at 1, 2, and 3 years, respectively (p = 0.2). Catheter survival has significantly increased over the last decade. Factors positively affecting PDC survival appeared to be the use of mupirocin for exit site care and the utilization of the coiled type of catheter, practices implemented mainly after 1999. Peritonitis-free survival and patient survival were not associated with the mode of placement, while in Cox regression analysis, were longer in patients treated with automated PD. The placement mode did not affect PD outcomes. Percutaneous implantation proved a safe, simple, low cost, immediately available method for PDC placement and helped to expand our PD program.

Percutaneous ethanol injection therapy: a surgery-sparing treatment for primary hyperparathyroidism.

OBJECTIVE: To describe our 3-year experience in the long-term efficacy and safety of percutaneous ethanol injection therapy (PEIT), as an alternative to surgery for the management of patients with primary hyperparathyroidism (p-HPT). DESIGN: Prospective study with a mean follow-up of 19.6 +/- 10.6 months. PATIENTS: Our study population included 19 consecutive high risk patients with p-HPT, who met the criteria for surgery. MEASUREMENTS: Under ultrasonic guidance, ethanol (95%) was injected into parathyroid glands with a volume of >or= 0.15 cm(3). With the aim of normalizing intact parathormone (iPTH) values, repeated ethanol injections were carried out, in an interval of 2 weeks, until normalization of iPTH was reached or until no residual blood supply was detected by ultrasound in the gland. Biochemical parameters were monitored throughout the study. RESULTS: At 6-month follow-up, normalization of iPTH levels (10-65 ng/l) was achieved in 11 (58%) patients (responders). Of the eight remaining patients (nonresponders), six patients had reduced (but not normalized) iPTH levels and two patients required parathyroid surgery. Seventeen (11 responders and 6 nonresponders) of the 19 patients (89.5%) became normocalcaemic (serum Ca 200 ng/l. The only complication was a transient dysphonia noticed in three patients. CONCLUSIONS: PEIT is a safe and effective nonsurgical treatment for patients with p-HPT, who are unsuitable for surgical intervention.

Total and corrected antioxidant capacity in hemodialyzed patients.

BACKGROUND: Oxidative stress may play a critical role in the vascular disease of end stage renal failure and hemodialysis patients. Studies, analyzing either discrete analytes and antioxidant substances, or the integrated total antioxidant activity of human plasma during hemodialysis, give contradictory results. METHODS: Recently, we have introduced a new automated method for the determination of Total Antioxidant Capacity (TAC) of human plasma. We have serially measured TAC and corrected TAC (cTAC: after subtraction of the interactions due to endogenous uric acid, bilirubin and albumin) in 10 patients before the onset of the dialysis session, 10 min, 30 min, 1 h, 2 h and 3 h into the procedure and after completion of the session. RESULTS: Our results indicate that TAC decreases, reaching minimum levels at 2 h. However, corrected TAC increases with t1/2 of about 30 min. We then repeated the measurements in 65 patients undergoing dialysis with different filters (36 patients with ethylene vinyl alcohol copolymer resin filter -Eval-, 23 patients with two polysulfone filters -10 with F6 and 13 with PSN140-, and 6 patients with hemophan filters). Three specimens were collected (0, 30, 240 min). The results of this second group confirm our initial results, while no significant difference was observed using either filter. CONCLUSIONS: Our results are discussed under the point of view of possible mechanisms of modification of endogenous antioxidants, and the interaction of lipid- and water-soluble antioxidants.